Ducati Monster Forum

I saw this on the web while reading about increasing fuel economy-

"Buy gas in the morning - gas is sold by volume and expands when warm. So fill the tank up early morning (dawn is the optimum time) when the gas is cold and dense. This way, when it warms up, it expands and you have more than you would have if you bought it warm."

Am I wrong to think this is false?

Aren't the tanks the fuel is kept in below the frost line, making the temp 55ish degrees no matter what time of day it is?

I've heard it was a myth based on the logic you point out. Too lazy to find a link to prove it's a myth though.

Scroll down...

http://www.snopes.com/inboxer/household/gastips.asp (http://www.snopes.com/inboxer/household/gastips.asp)

Thanks!

Maybe we can call you "Mr. Factfinder" too!

I'm calling him bubblehead squid.

Also, when it expands, it has to go somewhere. There has to be some sort of venting.

Not necessarily. Gas (the air in the tank, not the fuel) is compressible...

You may want to research that.  There is definitely a possiblility that cooler gasoline is denser and will therefore may pack a little more punch.

His mind only works in one plane...

temperature and density/volume are definitely related...

but Boyles' law doesn't apply if you're a bubblehead squid. ;D

(http://custom.bobbleheads.com/images/imagecache/Bobblehead_Navy_Bobblehead_Naval_Officer.jpg)


oh wait, you said bubble head....

close enough... ;D

It does make a slight difference, but is probably more related to the fuel being warmed by a hot vehicle that has been driving around/sun exposure vs a cold vehicle that has just been started/cooled off overnight.

I was responding to this...

please re-read my post (quoted below), looking closely at the words in bold


In other words, lighten the make the beast with two backs up, Francis.

I can change the mileage in G's truck by more than 3 mpg just by driving a little differently (while still moving with the faster traffic).    That's waaaay more than anyone would ever see due to temps in the gas station tanks.    To me this is one of those issues that can so easily be changed much more by other factors that it becomes irrelevant.  

Now bear with me cause I've had a six pack of tequila. As Staler said you would be better served to drive gently than believe any of the cooler in the morning horseshit. That big tank of fuel 10 feet under the ground aint changed much since last night. On another note, expanding fuel, or an overfilled tank makes a carbon canister say many bad words that can turn very expensive.

Now that is true.


Why do you think in professional racing they take the temperature of your fuel prior to qualifying?

You have x amount of degrees below ambient temperature

cooler fuel = more horsepower

at least that applies to methanol and ethanol.

Weren't there stories of Ducati riders showing up on the grid with frost on the tanks before the fuel temp regs went into place? IIRC, the reason wasn't to boost the energy of any given injector squirt of fuel, but to comply with the letter of the fuel VOLUME rules while actually putting more in the tank. Very clever...

But I'd think the diurnal temp change in an underground tank would be quite minimal (as opposed to sticking race fuel in the freezer)

Is it for power or volume? In the case of motorcycle racing...I think it is volume.

The volume difference isn't enough for a consumer to worry about...but racing is at the edge where little things matter. It would likely be a power thing for drag racing since the fuel doesn't have time to warm over the course of a race...and volume probably isn't an issue.

Quit agreeing with people on here...your reputation is in danger!

I think you're right.

You can fit more cold fuel in a 21 litre tank than warm fuel.

Ducati chills the fuel for the motogp bikes and puts a space blanket on the tank to keep it from expanding and running out the overflow.

My perspective comes from Indy Car Racing.

Cooler fuel = more horsepower.

Straight out of the mouth of several engineers and team managers.


There is a rule in the rulebook about it.

my buddy got busted in KY a few years ago during qualifying for it. His moronic gas guy left the methanol in the fridge too long.............

Interesting reading if you google it. Apparently the cooler fuel = more hp is related to the cold fuel cooling the intake air, not the actual temp of the fuel. Not sure if what I read was true...it's all beyond me.

I figured for a race of any length it would be related to volume, not hp as I figured the gas would quickly warm during the race nullifying any advantage. Maybe not I guess.  ???

Let me send him a text for the real explanation.

Your google research is correct.

Response from Ed:

"Yes, cool fuel makes more power, cools the intake. Motors run better in cool air. Cool fuel the air at intake"


I guess we can put this argument to rest about volume.


The same concept would apply to a motorcycle as well.

you can if you want to.

Hooray!

Check it. . .  you can put ice in it 8)

(http://www.jegs.com/images/photos/700/710/710-65125.jpg)

http://www.jegs.com/p/Moroso/Moroso-Insulated-Cool-Cans/747208/10002/-1 (http://www.jegs.com/p/Moroso/Moroso-Insulated-Cool-Cans/747208/10002/-1)

For Moto GP I suspect it's chilled to get every last drop in there.

Which could effect the aggressiveness of their fueling . .

which could in turn effect power output.

For F1, I think its all about power, since they can refuel during a race.  Whether it makes more power by cooling the intake air or not, it does do something.

I think cold fuel would allow more timing, or more compression (or both) as the chilled droplets would be capable of absorbing more heat which could stave off detonation just a little longer.

And if a F1 engine isn't on the ragged edge of self destructing I don't know what is.

Those things take every little edge they can find. :)

Finally...

someone gets it.

911 Turbos use a fuel cooler that is run off the air conditioning.  The fuel is used to cool the air charge going into the cylinder.

Want!

Certain '60s Fords had 1" thick 4-bbl carb spacers that had a couple of coolant bungs on them that were hooked to heater hoses to warm the carb faster in cold weather. Back in the drag racing days we took one along with a homemade cool can full of ice and a small 12V pump and circulated freezing water through the cool can and carb spacer. Seemed to have a very positive effect along with cooling the fuel line also. It would have been interesting to do actual dyno testing versus a plain phenolic carb spacer.

And the phenolic space would also help to prevent the fuel from boiling in the carb, no?

Wow, cooler fuel may actually better.  Contrary to some people's beliefs.  :o

In other news, fill up before your tank gets below half full, or else you'll suck the sludge in the bottom.













 :P

Yep, but wouldn't necessarily be less than ambient (or underhood) temp. The phenolic spacer's basically just an insulator, while the chilled spacer was cooooold.

^
That's some good advice right there.

I was an unwitting participant in this bogus lawsuit. I had to "Opt out" but to do so I had to find a receipt and some other stuff.

Discount club retailer Costco has agreed to settle a lawsuit regarding the temperature of gasoline in its fuel pumps. The class action lawsuit, brought by non-profit group Consumer Watchdog, alleged Costco was selling consumers less fuel than they paid for when gasoline temperature inside its fuel pumps rose above 60 degrees Fahrenheit.

http://www.retailerdaily.com/entry/13402/costco-cools-off-hot-fuel-lawsuit/ (http://www.retailerdaily.com/entry/13402/costco-cools-off-hot-fuel-lawsuit/)

which gives it more HP

not sure what else there is to argue about

My truck started getting better mileage after I installed set of chrome Trucknutz below the hitch, because it makes my fuel mixture 17% more awesome.  Now I fill up whenever I damn well please.


Thank you, Trucknutz!

Truck nuts are teh ghey

didn't AZ want to put those on his bike at some point?

[laugh]

LOL

<obvious joke> yeah, but they blocked the chin vent and his visor kept fogging <obvious joke>

If you wanted to go faster, why didn't you just run a Chevy??


( ;D )

I have a buddy who works in the pipeline area of fuel transport.  We had this discussion locally when gas was $5/gal.  He did indicate that for his job, they do check fuel temp when pumping and transporting to ensure a specific volume of fuel.  But they were transporting thousands of gallons opposed to the 4 gallons on our bikes or the 20-50 on our cars. 

Difference?  Yes.  Enough to change your life?  up to you, I'd say no.

I never meant to suggest that volume made a difference in any situation other than in a gp bike where fuel capacity is strictly monitored.

I still think it makes a difference in their lives.